Apple's new iMac has been plagued by random—but reproducible for some—freezing issues, and it appears that the ATI Radeon HD graphics card and its drivers could be to blame. According to users participating in official Apple support discussions (here and here), the iMac continues to run during the freeze, but users are unable to control the programs with mouse clicks or keyboard commands without rebooting. Apple is apparently aware of the issue, but at this point, no official fix has been released. Some users have even reported that the latest round of video driver updates have made the problem worse, although there is no evidence to suggest that the problem is widespread. [Appleinsider and Tech.co.uk]